Ken Livingstone's arrogance cost him Mayor's job, admits Tessa Jowell

Ken Livingstone lost the London mayoral election because of his reputation for 'arrogance', a senior government minister has claimed.

Minister for London Tessa Jowell told a fringe meeting at Labour's annual conference: 'There is nothing that alienates people more than what they see as the arrogance of power.'

Ms Jowell, who oversaw the party's mayoral campaign, also suggested the Labour candidate's prior length of service as mayor could have put voters off re-electing him.

Goodbye: Livingstone exits the political stage after his defeat by Boris Johnson, right

Tessa Jowell says Livingstone's long service as Mayor worked against him

'You have to assume that in modern politics longevity works against you,' she added at the Manchester meeting.

Her remarks underline a belief held by many in the London Labour party that Mr Livingstone should not be allowed to stand again because he represented the past.

However, she added during the debate on the London elections that after four years he would be a 'refreshed, reinvigorated' candidate and better placed to win than when he was the incumbent.

At the meeting, a string of senior London Labour figures voiced criticism of Mr Livingstone's mayoral campaign.

Councillor Steve Reed, leader of Lambeth council, accused the campaign of sending 'mixed messages' about Conservative candidate Boris Johnson.

'With one hand we said he was a buffoon and with the other we said he was a dangerous extremist,' said Mr Reed.

'Both things cannot be true, and the voters concluded that neither was true.'

Len Duvall, leader of the London Assembly Labour group, said: 'It doesn't matter how impressive your legacy and achievements, you are not going to win by that alone.

'We had mixed messages and were a bit late coming in to play.'

The comments came as Mr Livingstone's former communications director told how newspaper investigations 'appeared to confirm that (City Hall) grant-giving was influenced by favouritism'.

Joy Johnson's words bear out reports by the Evening Standard and represent the first significant admission by one of Mr Livingstone's inner circle about the scandal of Lee Jasper, the former mayor's race adviser.

He quit in March after sexually charged emails were published in which he said he wanted to 'honey-glaze' a married mother-of-three, a woman whose projects received £100,000 from London's City Hall on Mr Jasper's recommendation.

Six charities have been under investigation after receiving funds from the London Development Agency.

Race adviser Lee Jasper should have quit sooner, according to Livingstone's former communications chief

The probe was sparked by claims in the Evening Standard that hundreds of thousands of pounds was paid to the projects - many of which were linked to Mr Jasper - with little or nothing to show for it.

Today Ms Johnson said Mr Livingstone's decision to 'hang on' to Mr Jasper despite allegations of cronyism was 'wrong', 'doomed' and 'a mistake' which cost the mayor 'much political capital at a crucial time ... (for) someone who was ultimately a figure of secondary importance'.

Writing in the British Journalism Review, Ms Johnson said: 'When someone is in the eye of the media storm - on this occasion, Lee Jasper, Livingstone's equalities adviser - resignation must be swift.

'Our reasoning, that resignation would look like an admission of guilt, was a mistake.'

The consequence of the Jasper affair was, Ms Johnson said, 'an inability' for the Livingstone campaign to get back on the front foot.

'With a barrage of negative stories arising from leaked emails that appeared to confirm grant-giving was influenced by favouritism, which in turn led to allegations of cronyism, we were operating against a backdrop of hostile stories over a sustained period,' she added.

Ms Johnson was also fiercely critical of the Evening Standard, saying its coverage was unbalanced and its billboards had caused 'incalculable damage' to the Livingstone campaign.

However, she admitted that some of its stories were 'legitimate'.